Rapid identification and sequence analysis of intact proteins in complex mixtures

A method for m/z selectively arresting ion-ion reactions (ion parking) within the ion-ion reaction cell of a mass spectrometer system, said method comprising

• providing a reaction cell comprising reagent ions and a set of electrodes with one or more periodic RF confinement voltages applied to them wherein during ion-ion reactions in one or more dimensions of ion motion, ions have oscillatory motion frequencies that are primarily determined by their mass-to-charge ratios,
• applying one or more auxiliary voltage waveforms to one or more electrodes of the ion-ion reaction cell, during a period where ion-ion reactions are performed, such that a first set of frequency components of one or more of said auxiliary waveform voltages provides m/z selective kinetic excitation to the reagent ions,
• kinetically exciting analyte product ions produced from said ion-ion reactions within one or more selected m/z ranges, during said period where ion-ion reactions are performed, so as to partially or fully arrest the further reaction of said analyte product ions within said selected m/z ranges;
• wherein the one or more auxiliary voltage waveforms include a plurality of frequency components selected to kinetically excite, via resonant or near-resonant excitation, analyte product ions within the one or more selected m/z ranges, and a notch corresponding to the m/z of the analyte precursor ion.